WASHINGTON (Reuters) - Rolling back territorial gains by the Taliban and strengthening the Afghanistan army’s ability to fight will be two key objectives of President Donald Trump’s new strategy for the country, a senior administration official said on Tuesday.

U.S. President Donald Trump announces his strategy for the war in Afghanistan during an address from Fort Myer, Virginia, U.S., August 21, 2017. REUTERS/Joshua Roberts

Trump, in a televised speech on Monday, promised a stepped-up military campaign against Taliban insurgents who have gained ground against the U.S.-backed Afghan government.

In outlining his strategy to give the U.S. military more authority to make battlefield decisions, Trump did not provide a timetable for determining whether the mission is a success or how commanders would be able to judge progress.

The senior administration official said, however, that one general measure of progress was assessing how much and what territory is controlled by the Afghan government or by the Taliban and other extremist groups such as Islamic State’s Afghan affiliate.

“It’s also the estimated number of fighters, the presence of al Qaeda and ISIS, how strong are they, how many fighters do they have, how are their training camps, what are their finance networks like,” the official said, speaking on condition of anonymity.

Also key will be the effectiveness of the Afghan army and whether U.S.-led armed forces can help it seize control of some territory held by the Taliban, the official added.

Trump, who was reluctant to approve a deeper engagement in Afghanistan after 16 years of war, wanted to keep a close eye on whether progress is being made, the official said.

“I think we’re going to be taking the temperature continuously,” the official said. “I don’t think we expect to see any real gains materialize for at least six months. But from that point on, it’s going to be something that we essentially never stop evaluating.”

An Afghan National Army (ANA) soldier keeps watch at a checkpoint in Kabul, Afghanistan, August 22, 2017. REUTERS/Omar Sobhani

U.S.-backed Afghan forces overthrew the Taliban’s hard-line Islamist government in late 2001 because it sheltered al Qaeda chief Osama bin Laden, architect of the Sept. 11 attacks on New York and Washington that year.

U.S. forces have been bogged down since in a war that has vexed three American presidents. About 2,400 U.S. troops have died there in America’s longest military conflict.

‘PROGRESSIVE PROCESS’

Three U.S. officials said on Tuesday the administration had yet to settle on specific metrics to measure progress in Afghanistan and assess the contributions of the Afghan government, Pakistan, India and America’s NATO allies.

One of the officials said there was no point “in setting specific targets, much less making them public, because that would risk making our partners think that once they had met those marks, they didn’t have to do more.”

“What we’re after is a progressive process,” the official said, “so for example the Afghan security forces keep improving their capabilities until they don’t need us anymore, the government in Kabul keeps improving its record on eliminating corruption and improving local, regional and national governance.”

But Representative Adam Schiff, the top Democrat on the House Intelligence Committee, struck a critical tone on Tuesday.

“While a ‘conditions based’ approach is appealing to military leaders because it gives the Taliban less certainty about how long it will take to wait us out, it also diminishes pressure on the Afghan government to reform itself and give the Afghan people something worth fighting for, since it indicates a willingness to bail them out indefinitely,” Schiff said in a statement.